Japan's multi-billion-dollar pornographic industry has issued a formal apology and promised change after allegations that women have been forced to perform sex acts on film against their will.

The move comes after the arrest this month of three talent scouts accused of coercing a woman to perform in more than 100 porn films over several years.

One of those arrested was a 49-year-old executive at Tokyo-based agency Marks Japan, who was arrested on suspicion of violating the country's labour laws.

Pornography is widely available in Japan and some actresses become well known enough to appear on mainstream TV chat shows. Porn actresses wave to fans at the opening of a 2014 sex toy fair in Tokyo STOCK IMAGE

The talent agency allegedly pressed the victim, who thought she would be working as a model, to perform in adult videos by warning her she would have to pay penalties for breach of contract if she refused.

The high-profile case sparked the industry's response but campaigners said the practice was more widespread and welcomed the apology as 'the first of its kind'.

Some actresses have claimed they were forced to engage in repeated intercourse without protection and even being gang-raped during filming.

Human Rights Now, a Tokyo-based campaign group, said the number of women seeking counselling over industry abuses jumped more than 80 percent last year.

Japan's porn industry is worth billions of dollars and the industry body has said it would encourage producers to take action to improve the situation quickly STOCK IMAGE

The Intellectual Property Promotion Association, which represents Japan's adult film industry, said in it would 'encourage producers to take action to quickly improve the situation and restore the soundness of the entire industry'.

In a statement they said: 'The association deeply regrets that we had failed to take initiatives before. We are very sorry.'

Shihoko Fujiwara, a campaigner at Lighthouse, a non-profit group that helps human trafficking victims, has applauded the apology but pointed not one in five porn producers did not belong to the IPPA.